Sometimes God's commands make no apparent sense at all; when that is the case, it is because He does not want them to make sense to us. God does not do anything without a reason, and He can always be trusted absolutely to be devising good. Sometimes He just wants us to show that we understand that, so He gives us strange tests.
Without faith it is impossible to please Him, for he who comes to God must believe that He is, and that He is rewarder of those who seek him. (HEB 11:6)
To Abraham the test was God's command to sacrifice his "only son," the son through whom God had promised to make of him a great nation (GEN 22:1-2).
To the widow of Zarephath, who told Elijah she was about to cook her very last handful of flour and her last drops of oil and then lay down and die, the command was to first prepare bread for the prophet (1KI 17:13).
To the widow whose creditors were about to take her children, the command was to borrow jars from her neighbors (2KI 4:3).
To Namaan the leper, the command was to wash seven times in the Jordan River (2KI 5:10).
To the blind man, who had no doubt heard that Jesus could heal with a touch, the command was to go and wash in the pool of Siloam (JOH 9:7, JOH 9:11).
To Peter, who was being hassled about whether his Teacher paid the temple tax, the command was to go fishing (MAT 17:27).
What would have happened if these commands had been disobeyed? Nothing would have happened. If there had been no obedience, there would have been no miracles. If we really believe the Word of God, we are going to do something about it, no matter how contrary to reason its commands may seem.
This material was originally a highlighted topic in "The Basics". Additional topics can be found here.